The long range goal of the proposed research program is to determine the underlying physiologic and endocrinologic mechanism(s) that are responsible for the action of the hypothalamic peptide hormones in mediating sexual performance in animal and man. Studies will be conducted on the female rat to delineate further the specificity of action of the peptide hormones in facilitating and inhibiting lordotic behavior; to determine the peptide-sensitive CNS sites and pathways which mediate changes in sex behavior; to evaluate the relationship between peptide hormones and putative neurotransmitters in enhancing and inhibiting mating; to characterize the sexual behavior patterns and motivational components induced by hypothalamic peptides; and lastly to further establish a functional relationship between the CNS, hypothalamic peptide hormones, ovarian hormones, putative neurotransmitters and the regulation of the onset, maintenance and offset of mating behavior. It is hoped that the results of this research will have relevance and direct application to sexual dysfunction and population control in man.